Protective system for grade crossings



Oct. 1, 1929. D. c. DAVIS I 1,730,194

I I PROTECTIVE SYSTEM FOR GRADE CROSSINGS Filed Aug. 6, 1925 5 sheets sheet 1 .INVENTOR Oct. 1,1929. D. c; DAVIS PROTECTIVE SYSTEM FOR GRADE OROSS'IIWa Filed Aug. 6, 1925 3 Sheets-Sheet 2 inf INVENTOR I Oct. 1, 1929. I'D. c. DAVIS 1,730,194

PROTECTIVE SYSTEM FOR GRADE CROSSINGS Filed Aug. 6, 1925 3 Sheets-Sheet 3 4 WITNESSES: r

INVENTOR /4. 7

Patented Oct. 1, 1929 DAVID C. DAVIS, OF CHESTER, PENNSYLVANIA; MARGARET ELIZABETH DAVIS EXEGUTRIX OF SAID DAVID C. DAVIS, DECEASED PROTECTIVE SYSTEM FOR GRADE GROSSINGS Application filed August 6, 1925. Serial No. 48,574.

My invention relates to protective systems for grade crossings and it has for its object to provide distinctive warning signals to the crossing tender or gateman for each of several tracks which may be under his jurisdiction, a further object being the provision of means whereby the gates may not be opened when a train is in dangerous proximity on any of the tracks without the crossing tender being required to go to said track and manipulate an element in the system. These and other objects will be more manifest in the following detailed description.

In the accompanying drawing, Fig. 1 is a partial diagrammatic view showing one form of my invention wherein distinctive signals are given to a crossing tender or gateman for each of two tracks; Fig. 2 illustrates a modification of a. portion of the system' shown in Fig. 1; Fig. 3 is a view, partially diagrammatic and partially in section, illustrating another form of my device in which the gate tender is required to go into dangerous proximity to any given track should he desire to open the gate while a train is on said track in proximity to the crossing; and Fig. 4: is an enlarged view, in section, of the track element of Fig. 3; Fig. 5 is a view similar to Fig. 3 and illustrating the application of my invention to a different form of gate manipulating apparatus; and Fig. 6 is an enlarged view, partially in section, of the track element employed in the system of Fig. 5.

At the present time it is the common prac tice to equip the shanty of a crossing tender or gateman with a single gong, said gong being rung upon the approach of a train upon any one of two or more tracks which may traverse said grade crossing. As a result it frequently happens that a train passes the gate tender on the near track and, as the rear car of the train clears the crossing, he starts to open the gates, whereupon a train will suddenly appear on the further track, being obscured from view by said first mentioned train, with resultant accidents. which actually came to my attention within the last few months, a crossing tender on a In a case four-track crossing, although assisted by.

two special oflicers, raisedthe gates immediately after two trains had passed the crossing on a very foggy morning, with the result that a train 011 a third track suddenly appeared out of the fog and killed six people.

'In accordance with the simplest form of my invention, I largely avoid the aforementioned results by providing the gatemans shanty with distinctive gongs, lights or other indicating devices, one for each track, so that, irrespective of fog conditions or the simultaneous approach of trains on the different tracks, the gateman may ascertain the true condition of affairs before opening the gates.

In a further carrying out of my invention, I so arrange the gate opening mechanism that it is rendered inoperative should the crossing tender attempt to open the gates when a train is in proximity to the crossing and said mechanism cannot then be operated until the crossing tender goes into dangerous proximity to the track in question and resets the mechanism. Inasmuch as he will not do this latter act if there is any danger of being struck by a train, the degree of protection afforded is much increased. Means are also provided whereby the gates may be opened if a train is standing near the crossing, by special manipulation.

Referring to the drawing for a more detailed understanding of my invention, I indicate two tracks at 10 and 11, respectively, in Fig. 1, said tracks intercepting a highway 12 and thecrossing being guarded by suitable gates 13 and 14 of any well-known type. As shown, the gates are operated by a crank 15 manipulated .by a guard or 'gateman who is provided with the usual shanty 16. Disposed on or adjacent the shanty 16 are two gongs 17 and 18, preferably distinctive in sound the one from the other, the gong 17 being arranged to be rung upon the approach of a train on the track 11 and the gong 18 being arranged to be rung upon the approach of a train on the track 10. As indicated, the gongs 17 and 18 are connected across the respective rails through a battery or other current source 19 so that when a train comes within suitable insulating joints,-as shown at 2020, the short circuit between the rails caused by the wheels and axles of the train closes the circuit and rings the appropriate gong.-

I am well aware that crossing gongs are usually rung by a more complicated circuit, involving relays, etc. but inasmuch as such connection forms no part of the present invention, I have indicated the simplest possible track circuit; namely, the ordinary open circuit. Obviously the gongs 17 and 18 may be rung through any desired type of alarm circuit as is well known and understood in the art.

In operation, should the gong 18 ring for the approach of a train from the left on the track 10 and while said train obscures the view of track 11 toward the right, a train should approach from the right on the latter track, the gong 17 will thereupon be sounded,

clearly indicating to the gateman that the gates should notbe opened or raised.

Referring to the form of my invention I shown in Fig. 2, tracks 10 and 11 as before are connected through a battery 19 and a single gong 21, the circuit of the track 11 being closed through a pair of parallel con nected signal lights marked #1 and the circuit of the track 10 being closed through a pair of similar signal lights marl ed #2. Two lights are employed in parallel in each circuit sothat the burning out of one lamp does not give a false indication. If desired, a resistance member 22 may be connected in shunt relation to the winding of the gong 21 so as to permit a certain amount of current to flow through the lamps when the make-and-break mechanism of the gong is open, said resistance still being of suiiiciently high value to force adequateoperating current through the winding of the gong.

In operation, the approach of a train on the track 10 not only rings the gong 21 but lights the lights at #2, thus giving to the crossing tender a clear indication of the track 'in question, and should a train simultaneously approach on the track 11,the lights at #1 are also lit so that the gateman has a clear and unmistakable indication of the track conditions.

Referring'to the form of my invention shown in Figs. 3 and 4, tracks 10 and 11 are indicated as before and a gate 13 of any wellknown'type is arranged to be operated as by a bellows mechanism 25, including an upper chamber 26 and a lower chamber27 with an intervening flexible diaphragm, said diaphragrn being connected, as through a rack and pinion 28, to the gate. Air from any suitable source, either an air line running along the track or a pump operated by the gateman, flows through a pipe29 to a valve 30 whence it may be directed either to'the raising chamber 27 or .to the lowering chamber 26. As shown, the valve 30 is of the rotating type, being arranged to connect the and connected thereto to vent the pipe 31 under certain conditions as will hereinafter appear.

Referring to Fig. 1, the device 33 is shown more in detail and comprises a cylindrical casing 34 having a head 35 attached thereto and containing a movable valve member of the dumbbell piston type, as at 36. The pipe 31" enters at the left end of the casing 34:

and any pressuretransmitted thereby is eX- ertcd against the left-hand end of the valve member 36, the latter resting against an annular stop 37 so that air pressure from the pipe 31" has free access over the end thereof.

The member 36 is retained in the position shown by a latch member 38 engaging in a groove 39 therein, the latch member 38 being carried by the core 39 of a solenoid 40. A port 41 isprovided in the'casing 34 so as to .be closed by the member 36 in the position shown, the port 41 connecting with the open air, preferably through a whistle 42. A resetting plunger 43 projects through the cover member 35. The solenoid 40 for each device 33 'is connected in the track alarm circuit for the'associated track, as indicated in Fig. 3, said trackalarm circuit being of the general type above described in connection with Fig. 1. i i

In operation, let it be assumed that the gateman has lowered the gates vby the application of suitable air pressure through the chamber 26 so that the gate '13 is lowered, rather than being in the open position as indicated. Should a train then pass on the track 10 the core 39 of the device 33 associated with said track is raised, causing the latch'38 to disengage the valvernember 36, but no resultant action takes place because there is at that time'no air pressure on the line 31I Should the gateman attemptto raise the gate, however, before the train has, sufficiently cleared the crossing, the application of air pressure to the line 3131 will force the valve member 36 to the right, caus ing air to escape through the dotted port 41 and the whistle 42., "The free venting passage thus provided prevents the application of air pressure'to the chamber 27 and conse-- quently the gate cannot be raised or opened until the gateman turns the valve 30 to cut off a1r from the line 31 and then steps upon the track 10 and resets the valve 36 by pushing the plunger 43. In'like manner, should a train be passing on the track1O and the gate tender not observe the approach of a train on track 11, should he attempt to raise the gate when the train on the track 11 is within the signal zone, the pipe 31 will be vented at the track 11 and the whistle on track 11 will be blown so that the gate cannot be raised or opened until the gateman steps upon the track 11 and resets that valve. It can well be seen that he will not approach this track except with extreme caution, in view of the danger indicated. 7

While I have indicated the devices 33 as disposed between the rails of the respective tracks, they may equally well be disposed closely adjacent to the tracks at the sides thereof so as not to be struck and injured by dangling air hose, cinders, etc. It is obvious that they are in no way intended to be affected by contacting with any portion of the train and therefore they may well be disposed at the side of the track provided they are in sufficiently close proximity to the track so as to cause the gate tender to use caution in the resetting thereof in the face of an approaching train.

It frequently happens that a train approaches a crossing, causing the gatemen to lower the gates, and then comes to a stop, as when waiting for a block signal to clear. Un der these conditions it is permissible for the gates to be raised but with the apparatus thus far disclosed, this may not be done. Accordingly I may dispose a time-element switch adjacent. the track in question and operative to temporarily de-energize the solenoid 40 of the appropriate device 33, permitting the gate to be raised or opened.

Such a switch is indicated at 44 in Figs. 3 and 4 and embodies a switch arm 45 pivoted at 46 and normally resting on a contact member 47 connected to the lower terminal of the solenoid 40 to close the circuit through said solenoid. A biased dashpot 48 is connected to the switch arm 45, the piston thereof having a valved opening 49 of large area and a leak orifice 50 of small area, the valve flap of the opening 49 opening downwardly against a suitable spring.

If desired, a contact segment 51 may be disposed above the arm 45 and be connected to the upper terminal of the solenoid 40 through a resistor 52 having a resistance equivalent to that of said solenoid. A biasing spring 53 may assist in moving the arm 45 downwardly.

In normal operation, the arm 45 rests on the contact member 47 and the system operates as above described. If, now, a train approaches the crossing, causing the gateman to close the gates, and then comes to a stop, as for an adverse block signal, it is permissible for the gateman to open the gates. To

do this he manipulates the switch 44 at the track on which the train is standing, moving the switch arm 45 to the upper position,

this movement being permitted by the dashpot 48 through the opening of the valve at 49. The circuit of'the solenoid 40 is thus opened, the corresponding latch 38 falls and the gateman may temporarily admit air to the line 31-31 for the opening of the gates.

The switch arm 45 moves slowly down under the influence of the spring 53 and as permitted by theleak orifice 50 in the dashpot 48 until after, for example, thirty seconds, contact is re-established with 47, when the solenoid 40 is returned to service. I

It will be obvious that with the apparatus just discussed, the alarm device is out of commission during the interval the solenoid 40 is out of circuit, but the function of the contact segment 51 and its associated connections and resistor is to establish a shunt path around the solenoid 40 of equivalent resistance so as to actuate the alarm device temporarily. This shunt path may well be omitted if it is thought unnecessary to operate the alarm during said thirty-second interval, at tention being directed to the fact that the alarm circuit for the other track or tracks is unaffected by the manipulation of any particular switch 44. j

In practice it will, in general, be found preferable to employ an invertible glass tube of hour-glass type with suitable electrodes therein and a mercury contact globule with a filling of inert gas, such as neon, in place of the switch 44, as switches of this type are unafiected by dirt, water or climatic conditions. However, such switches are wellknown in the art and as they form no part of the present invention, it is unnecessary to encumber this specification with a detailed description thereof.

Referring to the form of my invention shown in Figs. 5 and 6, the result attained is similar to that indicated in the system of Figs. 3 and 4, but it is shown as applied to a gate of the mechanical operating type. The gate 13 is raised and lowered by a crank 15, a sprocket 55 on the crank shaft driving a flexible member 56 passing down over pulleys 57 and 58 and across the tracks to a pulley 59, passing directly beneath the tracks. The flexible member 56 embodies chain portions as indicated at 60 and 61. Referring to Fig. 6, the chain portion 60, for example, passes over a pillow block 61 just clearing a dog 62 pivoted at 63 and so weighted as to normally swing down into the chain 60. A member 64 bears against the left-hand end of the dog 62 holding said end against a fixed stop 65 so that the dog is held out of engagement with the chain. The member 64 is carried by the core 66 of a solenoid 67 so that as long as the solenoid 67 is energized to raise the core 66, the dog 62 rides on the chain,

but when the solenoid 67 is de-energized, the dog 62-is' held out of engagement with the chain.

Referring again to Fig. 5, the apparatus of Fig. 6 is mounted upon or immediately adjacent the respective tracks. The respective solenoids 67-67 are connected in the track circuits of an alarm system similar to that described in connection with Fig. 1- and may be temporarily de-energized by timeelement devices 68-68 as described in connection with Figs. 3 and 4.

In operation, should the gateman desire to lower or close the gates, the portion of the flexible member 56 shown closest to the rails moves toward the right so that irrespective of the position of the dogs 62-62, they merely ride idly on the chain portions 60 and 61. Likewise if the respective solenoids 6767 are de-energized because the crossing has been properly cleared by a train or trains, the'portions 60-61 can move toward the left for theraising or opening of the gates, the dogs 62-62 being held out of engagement by the respective core members 6666 in the released position thereof. Should it be attempted, however, to raise the gates when a train is in dangerous proximity on either track, the associated solenoid 6T raises the core member 66, permitting the dog 62 to drop upon the chain, and attempted motion of the latter toward the left causes the dog to pass through a link thereof, looking the chain against further movement and preventing opening of the gate. Under these conditions the gateman must slacken the chain slightly, go to the track in question and raise the dog 62 out of the chain before he can open the gate.

In the subjoined claims, mention is made of the energization of a circuit upon the approach of a train on a track. I am well aware that in so-called closed-circuit sys tems, the approach of a train and the resultant track short-circuit may de-energize a signal circuit and, by dropping a relay armature or equivalent element, close a local circuit for alarm purposes. I contemplate the use of this local circuit for performing the herein described functions in the same manner they are performed by the simple circuits shown by me and the claims should be construed accordingly.

the combination with atrack and an inter secting highway, of protective gates for said highway, operating mechanism. for said gates, and means for rendering said mechanism inoperative, should the gateman attempt to open said gates when a train is in proximity thereto.

2. In a grade crossing protective system, the combination with atra'ck, of protective gates therefor, operating mechanism for said gates, and means located, in part, indangerous proximity to said track and operative to render said mechanism inoperative, should the gateman attempt to open said gates when a train is in proximity thereto, whereby the gateman must approach said track to again render said mechanism operative.

3. In a multi-track grade crossing protective system, the combination with each track, of an electric circuit adapted to be energized when a train is on said'track in proximity to said crossing, a distinctive signal associated with each of circuits, respectively, to warn the gateman of the presence of a train on the associated track, protective gates, operatin mechanism therefor, and means associated with said circuits for rendering said mechanism inoperative should the gateman attempt to open the gates when a train is in proximity thereto on any of said tracks.

4. In a multi-track grade crossing protective system, the combination with each track, of an electric circuit adapted to be energized when a train is on said track in proximity to said crossing, a distinctive signal associated with each of said circuits, respectively, to Warn the gateman of the presence of a train on the associated track, protective gates, operating mechanism therefor, and means associated with each circuit and located, in part, in dangerous proximity to the associated track for rendering said mechanism inoperative should the gateman attempt to open said gates when a train is in proximity thereto, whereby the gateman must approach the track occupied by said train to again render said mechanism operative.

5'. In a grade crossing protective system, the combination with a pneumatically operated gate equipped with opening and closing pipes, of means for automatically bleeding said opening pipe should the gateman attempt to supply fluid thereto when a train is within a predetermined distance from said crossing. 1 i

.6. In a grade crossing protective system, the combination with a pneumatically operated gate equipped with opening and closing pipes, of means for automatically bleeding said opening pipe should the gateman attempt to supply fluid thereto when a train is within a predetermined distance from said crossing, said bleeding means being located in dangerous proximity to the track upon which said train is approaching, whereby the gateman must approach said track to terminate such bleeding action.

7. In a grade'crossing protective system, the combination With a pneumatically operated gate equipped with opening and closing pipes, of means for automatically bleeding said opening pipe should the gateman attempt to supply fluid thereto when a train is within a predetermined distance from said crossing, and means located in proximity to the track and operable by the gateman for temporarily preventing said bleeding means from operating.

8. In a grade crossing protective system, the combination with a pneumatically operated gate equipped with opening and closing pipes, of means for automatically bleeding said opening pipe should the gateman attempt to supply fluid thereto when a train is within a predetermined distance from said crossing, and means for temporarily preventing said bleedin means from operating.

9. In a grade crossing protective system, the combination with a protective gate, of opening and closing means therefor, means for disabling said opening means should the gateman attempt to operate the same when a train is in dangerous proximity to said crossing, and means whereby the gateman may temporarily prevent such disablement.

10. In a grade crossing protective system, the combination with' a protective gate, of opening and closing means therefor, means for disabling said opening means should the gateman attempt to operate the same when a train is in dangerous proximity to said crossing, and requiring that the gateman approach the track on which said train is approaching to attempt to remove said disablement, and means also located in proximity to said track whereby the gateman may temporarily remove said disablement in the presence of a train on said track.

11. In a. grade crossing protective system, the combination with a protective gate, of pneumatic operating means therefor embodying an opening pipe and a closing pipe, a vent located adjacent each track, respectively, means connecting said vents to said opening pipe, valve means for closing said vents, an alarm circuit associated with each track, respectively, and operative to give a distinctive indication of the presence of a train on said track, an electro-motor device associated with said circuit and operative, when said circuit is de-energized, to prevent the opening of the valve means and of the vent at the associated track, and to permit such opening when said circuit is energized, and manually operable reclosing means for said valve.

12. In a grade crossing protective system, the combination with a protective gate, of pneumatic operating means therefor embodying an opening pipe and a closing pipe, a vent located adjacent each track, respectively, means connecting said vents to said opening pipe, valve means for closing said vents, an alarm circuit associated with each track, respectively, and operative to give a distinctive indication of the presence of a train on said track, an electro-motor device associated with said circuit and operative, when said circuit is de-energized, to prevent the opening of the valve means and of the vent at the associated track, and to permit such opening when said circuit is energized, and manually operable means in proximity to each track for temporarily preventing said venting action in the presence of a train on said track.

18. In a grade crossing protective system, the combination with a protective gate, of pneumatic operating means therefor embodying an opening pipe and a closing pipe, a vent located adjacent each track, respectively, means connecting said vents to said opening pipe, valvemeans for closing said vents, an alarm circuit associated with each track, respectively, and operative to give a distinctive indication of the presence of a train on said track, an electro-motor device associated with said circuit and operative, when said circuit is tie-energized, to prevent the opening of the valve means and of the vent at the associated track, and to permit such opening when said circuit is energized, and a manually operable time-element switch in proximity to each track for temporarily removing said el-ectro-motor device from circuit, whereby said venting action may be prevented and the gate opened in the presence of a train on said track.

In testimony whereof, I have hereunto subscribed my name this 31st day of July, 1925.

DAVID C. DAVIS. 

